This house is called U Cerneho Orla (By the Black Eagle). On the same spot there was a pub but in 1889-90 a bank building was built. Today there is a medical centre there. The house is very pretty, definitely worth seeing while in Pisek.
At one corner of Alsovo Square, this beautiful building was originally built as a palace in late C19th. Exterior covered in sgrafitti. Not sure if you can go inside, as I understand it is now used for medical offices, but no harm in asking - if you speak Czech!